US 20 over Big Lost River
GoodButte County, Idaho · 16.4 E. Arco · Structure no. 000000000013200
- Built
- 1977
- 48 years old
- Condition
- Good
- inspected July 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 61 ft
- 1 main span
- Daily traffic
- 2,700
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
US 20 over Big Lost River is a prestressed concrete stringer/multi-beam or girder carrying US 20 over Big Lost River in Butte County, Idaho. It was built in 1977, so it is 48 years old, older than the Idaho average of 45.3 years.
The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 2,700 vehicles a day, roughly 18% of them trucks, projected to reach 4,050 by 2042. The structure is 61 ft (18.6 m) long and 40 ft wide. If it were closed, the detour would be 82 mi (132 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 8 Very Good | No problems noted. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US 20 over Big Lost River built?
It was built in 1977, making it 48 years old in 2025.
What condition is US 20 over Big Lost River in?
The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in July 2023.
How much traffic does US 20 over Big Lost River carry?
About 2,700 vehicles per day (2023 count), of which roughly 18% are trucks.
How long is US 20 over Big Lost River?
The structure is 61 ft (18.6 m) long with a longest span of 58 ft (17.7 m) and a deck 40 ft wide.
Who owns US 20 over Big Lost River?
It is owned by the State Highway Agency.